Ghostly, flowing supersolid? No, it's quantum plastic

IT’S one of the weirdest things predicted by quantum mechanics&colon; a solid that flows, ghostlike, through itself. As if that’s not enough to get your head round, experiments that claim to have made this “supersolid” may in fact have resulted in something completely different.

“We still do not understand the phenomenon. It’s something new,” says John Reppy, of Cornell University in Ithaca, New York, who claims to have glimpsed the new effect, dubbed quantum plasticity.

In a solid, atoms are bound together in a regular lattice, keeping their structure rigid under normal circumstances. But at certain temperatures supersolidity is …